Crystal structure of a fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 A resolution. EMBO J
ABSTRACT Fibrillarin is a phylogenetically conserved protein essential for efficient processing of pre-rRNA through its association with a class of small nucleolar RNAs during ribosomal biogenesis. The protein is the antigen for the autoimmune disease scleroderma. Here we report the crystal structure of the fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 A resolution. The structure consists of two domains, with a novel fold in the N-terminal region and a methyltransferase-like domain in the C-terminal region. Mapping temperature-sensitive mutations found in yeast fibrillarin Nop1 to the Methanococcus homologue structure reveals that many of the mutations cluster in the core of the methyltransferase-like domain.
Full-textDOI: · Available from: David Boisvert, Jun 01, 2014
- "Depending on the organism, fibrillarin mass ranges between 34 and 38 KDa and was originally described in the nucleolus of Physarum polycephalum (Christensen et al., 1977). It is included in the superfamily of the Rossmann-fold S-adenosylmethionine (SAM) methyltransferases (MTases) (Wang et al., 2000). The characteristics of this superfamily include a conserved SAM-binding motif, the catalytic triad/tetrad [K-D-K-(H)] and seven-stranded β-sheet flanked by α-helices to form an α-β-α structure (Rakitina et al., 2011). "
Article: Fibrillarin from Archaea to human[Show abstract] [Hide abstract]
ABSTRACT: Fibrillarin is an essential protein that is well known as a molecular marker of transcriptionally active RNA pol I. Fibrillarin methyltransferase activity is the primary known source of methylation for more than 100 methylated sites involved in the first steps of preribosomal processing and required for structural ribosome stability. High expression levels of fibrillarin have been observed in several types of cancer cells, particularly when p53 levels are reduced, because p53 is a direct negative regulator of fibrillarin transcription. Here we show fibrillarin domain conservation, structure and interacting molecules in different cellular processes as well as with several viral proteins during virus infection. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.Biology of the Cell 03/2015; 107(6). DOI:10.1111/boc.201400077 · 3.51 Impact Factor
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- "The RrmJ domain of 39 protein sequences and the three out-group proteins, fibrillarin (PDB code: 1FBN) , , vaccinia VP39 (1AV6)  and catechol-O- methyltransferase (1VID) , which are structurally and functionally similar to E. coli RrmJ, were used for the construction of a phylogenetic tree. The distance matrix was calculated using the JTT model. "
ABSTRACT: Ribosomal RNA large subunit methyltransferase J (RrmJ), an Escherichia coli heat shock protein, is responsible for 2'-O-ribose methylation in 23S rRNA. In mammals, three close homologs of RrmJ have been identified and have been designated as FTSJ1, FTSJ2 and FTSJ3; however, little is known about these genes. In this study, we characterized the mammalian FTSJ2, which was the most related protein to RrmJ in a phylogenetic analysis that had similar amino acid sequence features and tertiary protein structures of RrmJ. FTSJ2 was first identified in this study as a nucleus encoded mitochondrial protein that preserves the heat shock protein character in mammals in which the mRNA expressions was increased in porcine lung tissues and A549 cells after heat shock treatment. In addition, a recent study in non-small cell lung cancer (NSCLC) suggested that the FTSJ2 gene is located in a novel oncogenic locus. However, our results demonstrate that the expression of FTSJ2 mRNA was decreased in the more invasive subline (CL1-5) of the lung adenocarcinoma cells (CL1) compared with the less invasive subline (CL1-0), and overexpression of FTSJ2 resulted in the inhibition of cell invasion and migration in the rhabdomyosarcoma cell (TE671). In conclusion, our findings indicate that mammalian FTSJ2 is a mitochondrial ortholog of E. coli RrmJ and conserves the heat shock protein properties. Moreover, FTSJ2 possesses suppressive effects on the invasion and migration of cancer cells.PLoS ONE 03/2014; 9(3):e90818. DOI:10.1371/journal.pone.0090818 · 3.23 Impact Factor
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- "Suppressor strain S4 contains a mutation in NOP4 [nop4.S460L; Ser460(TCG) to Leu(TTG)], encoding a nucleolar protein with four RRM motifs that binds to the pre-rRNA in proximity of the 5’-end of the 5.8S rRNA and is required for the stable formation of pre-60S subunits containing the 27SA and 27SB pre-rRNAs [59–61]. Suppressor strain Sj comprises a mutation in NOP1 [nop1.M232K; Met232(ATG) to Lys(AAG)], coding for the methyltransferase component of C/D-box snoRNPs [62–66]. We first assessed the growth phenotypes of these three mutant alleles when expressed under the control of their cognate promoters from a centromeric plasmid (Figure S2A-C). "
ABSTRACT: Ribosomes are the molecular machines that translate mRNAs into proteins. The synthesis of ribosomes is therefore a fundamental cellular process and consists in the ordered assembly of 79 ribosomal proteins (r-proteins) and four ribosomal RNAs (rRNAs) into a small 40S and a large 60S ribosomal subunit that form the translating 80S ribosomes. Most of our knowledge concerning this dynamic multi-step process comes from studies with the yeast Saccharomyces cerevisiae, which have shown that assembly and maturation of pre-ribosomal particles, as they travel from the nucleolus to the cytoplasm, relies on a multitude (>200) of biogenesis factors. Amongst these are many energy-consuming enzymes, including 19 ATP-dependent RNA helicases and three AAA-ATPases. We have previously shown that the AAA-ATPase Rix7 promotes the release of the essential biogenesis factor Nsa1 from late nucleolar pre-60S particles. Here we show that mutant alleles of genes encoding the DEAD-box RNA helicase Mak5, the C/D-box snoRNP component Nop1 and the rRNA-binding protein Nop4 bypass the requirement for Nsa1. Interestingly, dominant-negative alleles of RIX7 retain their phenotype in the absence of Nsa1, suggesting that Rix7 may have additional nuclear substrates besides Nsa1. Mak5 is associated with the Nsa1 pre-60S particle and synthetic lethal screens with mak5 alleles identified the r-protein Rpl14 and the 60S biogenesis factors Ebp2, Nop16 and Rpf1, which are genetically linked amongst each other. We propose that these 'Mak5 cluster' factors orchestrate the structural arrangement of a eukaryote-specific 60S subunit surface composed of Rpl6, Rpl14 and Rpl16 and rRNA expansion segments ES7L and ES39L. Finally, over-expression of Rix7 negatively affects growth of mak5 and ebp2 mutant cells both in the absence and presence of Nsa1, suggesting that Rix7, at least when excessively abundant, may act on structurally defective pre-60S subunits and may subject these to degradation.PLoS ONE 12/2013; 8(12):e82741. DOI:10.1371/journal.pone.0082741 · 3.23 Impact Factor